Not searching for unused variables given on the command line.
-- The C compiler identification is GNU 13.3.0
-- The CXX compiler identification is GNU 13.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/bin/arm-openwrt-linux-muslgnueabi-gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/bin/arm-openwrt-linux-muslgnueabi-g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Checking for C++20 support
-- Performing Test COMPILER_SUPPORTS_CXX20
-- Performing Test COMPILER_SUPPORTS_CXX20 - Success
-- Not using fmt library
-- Build type Release
-- Using default linker. Other options are mold and lld.
-- Precompiled headers enabled
-- Found PkgConfig: /usr/src/openwrt/staging_dir/host/bin/pkg-config (found version "2.2.0")
-- Checking for module 'avahi-client'
-- Found avahi-client, version 0.8
-- Checking for module 'alsa'
-- Found alsa, version 1.2.11
-- Version 23.12~219~g7c563
-- Configuring done (0.4s)
-- Generating done (0.0s)
-- Build files have been written to: /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12
touch /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/.configured_68b329da9893e34099c7d8ad5cb9c940
rm -f /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/.built
touch /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/.built_check
MAKEFLAGS="" /usr/src/openwrt/staging_dir/host/bin/ninja -j1 -C /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12
ninja: Entering directory `/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12'
[3/93] Building CXX object lib/CMakeFiles/rtpmidid-shared.dir/rtpmidipacket.cpp.o
FAILED: lib/CMakeFiles/rtpmidid-shared.dir/rtpmidipacket.cpp.o
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/bin/arm-openwrt-linux-muslgnueabi-g++ -DRTPMIDID_VERSION="\"23.12~219~g7c563\"" -Drtpmidid_shared_EXPORTS -I/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/src -I/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/include -Os -pipe -fno-caller-saves -fno-plt -fhonour-copts -mfloat-abi=hard -fmacro-prefix-map=/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12=rtpmidid-23.12 -Wformat -Werror=format-security -fstack-protector -D_FORTIFY_SOURCE=1 -Wl,-z,now -Wl,-z,relro -DNDEBUG -fPIC -std=c++20 -Wall -Werror -O2 -D_REENTRANT -Winvalid-pch -include /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/lib/CMakeFiles/rtpmidid-shared.dir/cmake_pch.hxx -MD -MT lib/CMakeFiles/rtpmidid-shared.dir/rtpmidipacket.cpp.o -MF lib/CMakeFiles/rtpmidid-shared.dir/rtpmidipacket.cpp.o.d -o lib/CMakeFiles/rtpmidid-shared.dir/rtpmidipacket.cpp.o -c /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/lib/rtpmidipacket.cpp
In file included from /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/include/rtpmidid/formatterhelper.hpp:30,
from /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/include/rtpmidid/exceptions.hpp:23,
from /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/lib/precompile.hpp:23,
from /usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/lib/CMakeFiles/rtpmidid-shared.dir/cmake_pch.hxx:5,
from <command-line>:
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format: In member function 'std::string rtpmidid::packet_midi_t::to_string() const':
/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/include/rtpmidid/rtpmidipacket.hpp:118:23: in 'constexpr' expansion of 'std::basic_format_string<char, int, bool, bool, int, int, int, int, unsigned int, int>("RTP Packet: V:{} P:{} X:{} CC:{} M:{} PT:{} Sequence:{} Timestamp:{} SSRC:0x{:08X}")'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3751:19: in 'constexpr' expansion of '__scanner.std::__format::_Checking_scanner<char, int, bool, bool, int, int, int, int, unsigned int, int>::<anonymous>.std::__format::_Scanner<char>::_M_scan()'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3559:30: in 'constexpr' expansion of '((std::__format::_Scanner<char>*)this)->std::__format::_Scanner<char>::_M_on_replacement_field()'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3613:60: error: call to non-'constexpr' function 'void std::__format::__unmatched_left_brace_in_format_string()'
3613 | __format::__unmatched_left_brace_in_format_string();
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:167:3: note: 'void std::__format::__unmatched_left_brace_in_format_string()' declared here
167 | __unmatched_left_brace_in_format_string()
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format: In member function 'std::string rtpmidid::packet_command_in_ok_t::to_string() const':
/usr/src/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/rtpmidid-23.12/include/rtpmidid/rtpmidipacket.hpp:282:23: in 'constexpr' expansion of 'std::basic_format_string<char, rtpmidid::command_e, unsigned int, unsigned int, unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >("RTP Command Packet: Command:{} Protocol:{} Initiator: {} SSRC:{:08X} Name:{}")'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3751:19: in 'constexpr' expansion of '__scanner.std::__format::_Checking_scanner<char, rtpmidid::command_e, unsigned int, unsigned int, unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::<anonymous>.std::__format::_Scanner<char>::_M_scan()'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3559:30: in 'constexpr' expansion of '((std::__format::_Scanner<char>*)this)->std::__format::_Scanner<char>::_M_on_replacement_field()'
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:3613:60: error: call to non-'constexpr' function 'void std::__format::__unmatched_left_brace_in_format_string()'
3613 | __format::__unmatched_left_brace_in_format_string();
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/src/openwrt/staging_dir/toolchain-arm_cortex-a7+neon-vfpv4_gcc-13.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/include/c++/13.3.0/format:167:3: note: 'void std::__format::__unmatched_left_brace_in_format_string()' declared here
167 | __unmatched_left_brace_in_format_string()
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ninja: build stopped: subcommand failed.
git bisect revealed that commit 7c56354 introduced a build regression which makes it impossible to build rtpmidid on 32-bit platforms (x86/64 as well as aarch64 were tested and work fine, 32-bit ARM, x86, PPC and MIPS builds all fail).